Hi. I would like to suggest the usage of the tool's name instead of common namelist.input. I see that under Mesh Tools, each grid_rotate, periodic_quad, and periodic_hex use namelist.input as the namelist file. I'm suggesting for them to use namelist.grid_rotate, namelist.periodic_quad, and namelist.periodic_hex instead.
For example, in a workflow, that may call for at least periodic_hex and periodic_quad, currently both would refer to namelist.input. While this can be deal with the use of 'ln -sf' each time for each tool, it can be better if both of them would read their own namelist.periodic_hex and namelist.periodic quad.
There will be less confusion and less human error in using the tools.